CA1206256A - Compact, adjustable antenna - Google Patents
Compact, adjustable antennaInfo
- Publication number
- CA1206256A CA1206256A CA000439634A CA439634A CA1206256A CA 1206256 A CA1206256 A CA 1206256A CA 000439634 A CA000439634 A CA 000439634A CA 439634 A CA439634 A CA 439634A CA 1206256 A CA1206256 A CA 1206256A
- Authority
- CA
- Canada
- Prior art keywords
- antenna
- base member
- loop
- antenna apparatus
- antenna element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/29—Combinations of different interacting antenna units for giving a desired directional characteristic
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
- H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
- H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
- H01Q5/48—Combinations of two or more dipole type antennas
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/06—Details
- H01Q9/10—Junction boxes specially adapted for supporting adjacent ends of divergent elements
- H01Q9/12—Junction boxes specially adapted for supporting adjacent ends of divergent elements adapted for adjustment of angle between elements
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
- Support Of Aerials (AREA)
- Details Of Aerials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An antenna apparatus has a first wire-like antenna element formed into a rectangular planar loop and a second antenna element which comprises two L-shaped plates electrically connected to the loop and mounted to a rectangular planar base member. The loop is hinged to the planar base member along long sides of the respective rectangles so that the angle between the planes of the loop and base member is adjustable. The base member pivots about an axis on a mount which can be secured to a television receiver.
An antenna apparatus has a first wire-like antenna element formed into a rectangular planar loop and a second antenna element which comprises two L-shaped plates electrically connected to the loop and mounted to a rectangular planar base member. The loop is hinged to the planar base member along long sides of the respective rectangles so that the angle between the planes of the loop and base member is adjustable. The base member pivots about an axis on a mount which can be secured to a television receiver.
Description
SOlB50 A~ nu.~ u~
BACXGROUND OF THE INVE~TION
Field of the Invention The present invention relates to an antenna apparatus ~nd, moxe partic~larly f to a compact, indoor antenna for a televi~ion receiver~
Descri tion of the Prior Art P
Prior art television antennas consist of o~P~inlensional el~ments. Commonly ~uch antennas are either monopoles, comprising one antenna element, or dipoles r cvmprising two universally movable antenna elements con.nQc~e~ in ~he famil.ar ~rabbit ear" configuration.
~ signiicant ~rawback with ~uch prior art anter.~nas i.s the amol~nt of space they reguire :Eor proper operati.oY1. For ~xample, when low~bancl VHF ~ignals ~hannel~
1.-3~ are to be receiveti, each one-dimen~ional antt~nna ~lement needs ~o ~e adjus~ed to b~ abou~ 30 c~m long. Since ~uch ~ntennas are placed on the television ~et, which is commonly pu~ near a wall, optimum directional adjus~men~ of ~uch an~ennas, or example, in inclined positions, i6 often ~mpossible.
~ aXing the antenna smaller does not solve the problemO If the antenna is ~maller, the antenna prof~ciency i~ decreas~d because radiation resi~tance decreases or ~eeause impedance matching between the antenna and the line lea~ing to the te1eYi~iOn recei~er becomes very difficult, part~cularly in view of the wide band characteristic~ of ~elevi~ion ~ignal~.
~2~ ~ -OBaECT ~D SUMMARY OF TH]E INVENTION
Accordingly, i~ is an object o the prese~t --in~en~ion to provide an antenna appara~us which avoids the men~.ioned shortcomings of ~he prior art.
It is another object of the present invention to prov.ide an antenna apparatus which can be made small enough for use indoors and which is suitable for association wi~h a ~eIevision receiver.
In accordance with an aspect of the present inventi.on 3 an antenna ~pparatus comprises a multi-d~,merlsional fir~t antenna element, a multi-dimensional secolld ~ntenna element ro~atably mounted -to the first arltenna element for adjustment of the încluded angl.e between ~he .;ln~enna elements, and connecting means Eor electIically co~ec~ing the two antenna elements.
The above, and other o~ject~;, features, and adv~n~ages of the present invention, will be apparent in ~he ollowin~ ~etailed description of an ~mbodiment thereof.
BRIEF DESCRIPTION OF THE DRAWING
FIG. l is a 6chematic view of antenna elements in an antenn~ ~pparatus in accordance with ~ embodiment of the present inventionO
FI~. 2 is an i.~ometric view of a ~tructural arrangement of an antenna apparatu~ including ~he ~ntenna elemen~ts ~hown in FIG. 1~
FIG~ 3 is ~ ~chematic view of the antenna elements ~hown ~n E`IG~ l and indicating preferred dimensions thereof~
FIGS~ 4 6 ~raphically illustrate the perfonmance characteristic of the antenna apparatus o the present inverltion~
S~1~50 ~ETAILED DE5CRIPTION OF THE PREFERRED EMBODIMENTS
~ eferring in detail to FIG l, it will be seen that an antenna apparatus emboding th~ present invention esserlt.i~lly comprises a two-dimensional first antenna element 3Q in the form of a generally rectangular loop of conductive wire mounted to a ~wo-dimensional second antenna elem2nt c~nstituted by a plurality of L-shaped conductive plates 10 and 20. The first plate 10 has two legs 11 and 12. ~he le~ 12 tapers to a first contact point 13 at Gne Pnd thexeof~ The second piate 20 ~lso has two legs 21 and ?2~ The leg 22 tapers to a second contact point 23. Th~
~wo plates 10 and 20 are ~isposed in the same plane with the ent~s o:f the lQgs 12 and 22 in mutually facing relationship.
The legs 1 I and 21 have uniform widths, are of the same l.en~h, and are parallel to each o~her.
I.rhe ir~t antenna element 30 is desirably of a conductive wire bent into a generally rectangular loop lying in a flat plalle. Vne long ~ide of the rectangle is comprised of the legs 31 and 32, be~ween the ends of which there is ~ gap~ ~he opposi~e lony side 33 of the loop has a central offset portion 34~
The first antenna element 30 and the second antenna element comprised o~ plates ~0 ~nd 20 axe ro~atably mounted to each other so tha~ an angle ~ insluded between ~heir respective planes is a~justable. The two antenna element~ ~0, 20 ~nd 30 are electrical~y connected together, or exalnpt.e~ by two coil ~prings 41 and 42. Eash ~oil ~prin~ 41~ 42 includes a wound portion which encircles the x~5pective l.eg 31, 32~ The ends of the ~il springs 5018~0 ~rmina~e in fingers secu~ed to ~he legs 1~ and 21 of -~he pl~e~ lO and 20.
A matching cireuit 50, ~omprising a plurali~y of ~apaeit~rs and inductors arranged as ~hown on FIG. 1, is connec~ed between contact points 13 and 23 and a coaxial ~able 51 ~hich feeds the signal received by the antenna to a television receiver. The impedance of a typical coaxial cable is 75 ohms ~Q ) and ~he matching circuit 50 ma~ches ~he impedance of the antenna apparatus to that of the eoaxial eable 51.
The above described antenna apparatus is ~uitable for use as a VHF antenna for a television receiver.
It is pos~ible to also provide a UHF antenna in ~he antenna apparatus Pmobodying the present inventionO For this purpose ~ a third antenna element comprisea o~ two conductive plate member~ 61 and 62 is disp~sed in ~he plane of the plates 10 and 20. The plates 61 and 62 are generally txapeæ~idal and ~aper to contact points 63 and 64 of their adjacent ends~ A matching circuit 70 matches ~he impedance of the third antenna element to the impedance of a conventiQnal flat, dual~element antenna wire 71, which t~pically has an impedance of 300 Q.
Referr~ng now tv FIG. 2, it will be seen ~hat ~he ~econd ~ntenna element desirably includes a base member lOG
made of a plastic material~ ~uch as ~BS (acrylonitrile;
butadiene-styrene) cop~ly~er. ~he v~rious plate member~ 10, 20, 61 ~nd ~2 are ~ecured to ~he base member lOO by ~yelets, th~rmal weldi~g, or ~ther ~uit~le mea~ he impedance ma~shing circuits 50 and 70 ~an be ~abricated ~ circuit ~01~50 ~ S83P21 boards which can also be secured to, or housed in base men~b~r 100.
The base member 100 has secured to it a pair of hinge blocks lll and 112. The hinge blocks is lll and ll~
have ~ores through which legs 31 and 32 of loop 30 rotatably extend, The ends of the legs 31 and 32 ar~ held rotatably in a rearwardly extending tongue lOOa formed centrally on base ~ember 100. The hinge blocks 111 ~nd 112 and tongue lOOa support the loop 30 for rotation relative to the base me~ber lO0 to change the included angle ~ between the ~rltenr,a elements. The hinge blocks lll and 112 include ~roo~es 131 for a purpose described below. In the ront edge vf the base memher lOC, a notch 132 is provided. The offse~ portion 34 of the loop 30 is adapted to resiliently engage in the notch 13~ when the loop is folded (~ = 0) for stoxage or when the antenna apparatus is no~ being us~.
The base me~ber lO0 further has a downwardly ex~ending shaft 1410 A face gear 142 is mounted on a boss 143 molded integrally with the base me~mber 100~ The ~ha~t 141, which typically i~ made of metal (for m~ximum durability), i5 embedded in the bo~ 143 and is ~urrounded ~ the ~ace year 142. 'The shaft 141 provides a mounting means for the antenna apparatusO A moun~ 151y which csn be ~ecuxed tD the televison receiver, has a central hole 152 ~olded therein f~r r~tatably ~ccepting ~he ~haft 141~ ~he antenna apparatus can thu~ be rotated in ~he plane of base ~ember lO0 a~out the axis defined by shaft l~l~ The ~ount 151 also includes a ~aee ~ear 153 which confronts and ~cooper~tes with face ge~r 142 to prevent inadverta~t rotation vf the a~te~nh appar~tu~ . Thus I when he an enna 0~
S~1850 S~3P21 app~ratus has been directionally oriented, it is held in plac~ ~y ~ixing means, c~mprised of the faee gears 142 and 153~ again~t external r~tationa]. forces~ such as~ -that exexted by coaxial cable 51 when the antenna apparatus is ro~a~ed~
Referring n~w to FIG. 3, it will be seent ha~ an antenna apparatus in accordance with the present invention is very compact as compare~ ~ith the known one dimensional antenn~. ~lements commonly used in the prior art. Typic~lly, the total length ~1 of the operative antenna sho~n in FIG.
3 is sli~htly in excess of l meter~ which is about 0.3 to 0~35 ~imes the wavelenyth of signals in the ~HF low-band~
~ith such value of the lenyth 21o the antenna ~ecomes parallel-re~onall~ with signals having a ~requency of about 150 MHz, the wavelength ~f wh.ich is about 2 meters. It will ~urther be seen that the dimensions of the loop 30 and of ~he ~lates 10, 20, all of ~h~ch are shown in millimeters, ar~ such ~hat the L-shaped plates 10l 20 and the plates 61, ~2 therebe~ween can nest within loop .iO when the latter is foldedu E'IG. 4 graphically illust~ates the resi~tance R
~nd xeactance X in ohms (Q~ plotted again~t 21/~ , where 21 is the length of a loop, as ~hown in FIG. 3~ and ~
~epresent~ the wavelength 9f the ~ignal being received. As FIGo ~ illustrates5 with a ~iqnal o~ abou~ lOOMHz ~he wave:length of which is about 3 meters~ the r actance X is inductive, ~nd the reactanc~ becomes capac~tative with ~a ~ignal of ~bout 200~Hz J the wavelength of which i~ ~b~ut 1 D 5 m~ters. The ~esi~tance comp~nent i~ a~ut 10.~ a~ lOO~z and ~bout 100 Q ~t 200P~z. In ~he VHF high-band ~channels 4-12, S~185~
or freqllencies between about 170 MHz and 222 MHz) such a ~ntDJlna can be madP wide-band resonant by ~irtue of the ma~Ghing circuit 50 to provide coverage of the entire VHF
~igh~b~d. For the YHF low-band (frequencies of between 90 ~z and 108~.Hz), however, since the radiation resistance is sm~ the receiving bandwidth is decreased and neither the whole V~F low-band nor the requisite 6MHz bandwidth can be co~ered under ~hose conditions. Although for VSWR (Voltage ~Standlng Wave Ratio) values of about 2 to 3, the requisite ch2nnel bandwidth can be o~tained, it still is no~ possible ~o oover ~he entire VHF low-bandO However, in the antenna apparatus according to the presen~ invention, ~he adjustability of the angle ~ enables the coupling capclcitance to be changed so that the resonant frequency ~an be changed for each channel in the VH]? low band, and the entire low-band region of the VHF also can be covered by the antenna appaxa~us of the present invention.
FI~. S is a Smith chart which graphically illustxate6 the impedance characteristics of the antenna ~mboding the present i~vention for various values of the ~n~le (3 ~ The solid li~e in ~IG. 5 represents the impedance a~ ~- 180 and the do~ted line represen~s the impedance at ~- 0~O The impedance is ~hown for various frequencies ~90~z~ 93MHz, 105MHz and 220MHz~ Note tha~ the impedance characteristics of the antenna for ~ 0 and = lB0 are the ~ame ~bove a certain frequency~
FIG. 6 ~hows t~e gain characteristie~ of the an~enna ~pparatus of the presenk invention. In FI~ h2 ~oIid lines represent the antenna apparatus of the present invention and the dashed lines repre5ent the values fo~
;8 dlpole antenna, such ~s the rabbit ears used in the prior ar~ 6 illus~rates ~hat the small, compact antenna as ~hown .in FIG. 3 has impedance and gain characteristie~
~omparab`le to the characteristics of a dipole antenna having ~ntenn~ elements about 90 cm. long.
The antenna apparatus of the present invention is ~hus a wide-band resonan~ type in ~he high~band region of VHF ~ignals and is also resonant at Pach channel ~requency in ~he k~w-band xegior~ of the VHF signals, where radiation resistanee is small, by virtue of th~ ~apability of varying ~he ang~e ~.
It is, c course, known in the prior art that the resonant requency of an antenna can be changed with a ~a;racto~ diode. However, such ~evices are disadvantageous because ~hey require a control voltage, which increases the cost of ~he antenna~ and because non-linear distortion can be produced in the presence of the resulting electrical fieldO Eowever, with t.he present inY~ntion ~ ~uch increases in cost are prevented and non linear distortion is avoided becau~e it is the adjustment o the anyle ~ which varies ~he resonant: ~requency of the antennaO Furthermore, the grooves 131 in ~he blocks 111 and 112 enable the angle ~ to be set in sueh a way that it w.ill no~ be inadvertantly changed.
As th~se ~killed in ~e art will appreciate; the gain ~ the present antenna ~pparatus is increased because the legs 12 ~nd 22 of the plates 10 and 20~ respec~ively~
tap2r to ~he ~ontact point~ 13 and 23 ~o tha~ the voltage at .hose points i~ increased~ The leg p~rtion~ 1 and 3~ o~
the loop 30 al50 increase the gain of the antenn~ apparatus of ~he p~esent invention~
_.9 ~6~i S83P214 The pr~sent invention has been described in connec~ion with particular ~tructure. Those skilled in the art ~il1 cecognize var.iou~ modifications other than those ~pecifically pointed out which can be made to the embQdimen~s o he present invention described herein without departing from the spirit of the inventivn. For ex~mplel the two antenna elements can be made in more than ~wo dimensions. Th~refore t the ~cope of the present ;nvention is defin2d solely by the claims which follow.
~ 10-
BACXGROUND OF THE INVE~TION
Field of the Invention The present invention relates to an antenna apparatus ~nd, moxe partic~larly f to a compact, indoor antenna for a televi~ion receiver~
Descri tion of the Prior Art P
Prior art television antennas consist of o~P~inlensional el~ments. Commonly ~uch antennas are either monopoles, comprising one antenna element, or dipoles r cvmprising two universally movable antenna elements con.nQc~e~ in ~he famil.ar ~rabbit ear" configuration.
~ signiicant ~rawback with ~uch prior art anter.~nas i.s the amol~nt of space they reguire :Eor proper operati.oY1. For ~xample, when low~bancl VHF ~ignals ~hannel~
1.-3~ are to be receiveti, each one-dimen~ional antt~nna ~lement needs ~o ~e adjus~ed to b~ abou~ 30 c~m long. Since ~uch ~ntennas are placed on the television ~et, which is commonly pu~ near a wall, optimum directional adjus~men~ of ~uch an~ennas, or example, in inclined positions, i6 often ~mpossible.
~ aXing the antenna smaller does not solve the problemO If the antenna is ~maller, the antenna prof~ciency i~ decreas~d because radiation resi~tance decreases or ~eeause impedance matching between the antenna and the line lea~ing to the te1eYi~iOn recei~er becomes very difficult, part~cularly in view of the wide band characteristic~ of ~elevi~ion ~ignal~.
~2~ ~ -OBaECT ~D SUMMARY OF TH]E INVENTION
Accordingly, i~ is an object o the prese~t --in~en~ion to provide an antenna appara~us which avoids the men~.ioned shortcomings of ~he prior art.
It is another object of the present invention to prov.ide an antenna apparatus which can be made small enough for use indoors and which is suitable for association wi~h a ~eIevision receiver.
In accordance with an aspect of the present inventi.on 3 an antenna ~pparatus comprises a multi-d~,merlsional fir~t antenna element, a multi-dimensional secolld ~ntenna element ro~atably mounted -to the first arltenna element for adjustment of the încluded angl.e between ~he .;ln~enna elements, and connecting means Eor electIically co~ec~ing the two antenna elements.
The above, and other o~ject~;, features, and adv~n~ages of the present invention, will be apparent in ~he ollowin~ ~etailed description of an ~mbodiment thereof.
BRIEF DESCRIPTION OF THE DRAWING
FIG. l is a 6chematic view of antenna elements in an antenn~ ~pparatus in accordance with ~ embodiment of the present inventionO
FI~. 2 is an i.~ometric view of a ~tructural arrangement of an antenna apparatu~ including ~he ~ntenna elemen~ts ~hown in FIG. 1~
FIG~ 3 is ~ ~chematic view of the antenna elements ~hown ~n E`IG~ l and indicating preferred dimensions thereof~
FIGS~ 4 6 ~raphically illustrate the perfonmance characteristic of the antenna apparatus o the present inverltion~
S~1~50 ~ETAILED DE5CRIPTION OF THE PREFERRED EMBODIMENTS
~ eferring in detail to FIG l, it will be seen that an antenna apparatus emboding th~ present invention esserlt.i~lly comprises a two-dimensional first antenna element 3Q in the form of a generally rectangular loop of conductive wire mounted to a ~wo-dimensional second antenna elem2nt c~nstituted by a plurality of L-shaped conductive plates 10 and 20. The first plate 10 has two legs 11 and 12. ~he le~ 12 tapers to a first contact point 13 at Gne Pnd thexeof~ The second piate 20 ~lso has two legs 21 and ?2~ The leg 22 tapers to a second contact point 23. Th~
~wo plates 10 and 20 are ~isposed in the same plane with the ent~s o:f the lQgs 12 and 22 in mutually facing relationship.
The legs 1 I and 21 have uniform widths, are of the same l.en~h, and are parallel to each o~her.
I.rhe ir~t antenna element 30 is desirably of a conductive wire bent into a generally rectangular loop lying in a flat plalle. Vne long ~ide of the rectangle is comprised of the legs 31 and 32, be~ween the ends of which there is ~ gap~ ~he opposi~e lony side 33 of the loop has a central offset portion 34~
The first antenna element 30 and the second antenna element comprised o~ plates ~0 ~nd 20 axe ro~atably mounted to each other so tha~ an angle ~ insluded between ~heir respective planes is a~justable. The two antenna element~ ~0, 20 ~nd 30 are electrical~y connected together, or exalnpt.e~ by two coil ~prings 41 and 42. Eash ~oil ~prin~ 41~ 42 includes a wound portion which encircles the x~5pective l.eg 31, 32~ The ends of the ~il springs 5018~0 ~rmina~e in fingers secu~ed to ~he legs 1~ and 21 of -~he pl~e~ lO and 20.
A matching cireuit 50, ~omprising a plurali~y of ~apaeit~rs and inductors arranged as ~hown on FIG. 1, is connec~ed between contact points 13 and 23 and a coaxial ~able 51 ~hich feeds the signal received by the antenna to a television receiver. The impedance of a typical coaxial cable is 75 ohms ~Q ) and ~he matching circuit 50 ma~ches ~he impedance of the antenna apparatus to that of the eoaxial eable 51.
The above described antenna apparatus is ~uitable for use as a VHF antenna for a television receiver.
It is pos~ible to also provide a UHF antenna in ~he antenna apparatus Pmobodying the present inventionO For this purpose ~ a third antenna element comprisea o~ two conductive plate member~ 61 and 62 is disp~sed in ~he plane of the plates 10 and 20. The plates 61 and 62 are generally txapeæ~idal and ~aper to contact points 63 and 64 of their adjacent ends~ A matching circuit 70 matches ~he impedance of the third antenna element to the impedance of a conventiQnal flat, dual~element antenna wire 71, which t~pically has an impedance of 300 Q.
Referr~ng now tv FIG. 2, it will be seen ~hat ~he ~econd ~ntenna element desirably includes a base member lOG
made of a plastic material~ ~uch as ~BS (acrylonitrile;
butadiene-styrene) cop~ly~er. ~he v~rious plate member~ 10, 20, 61 ~nd ~2 are ~ecured to ~he base member lOO by ~yelets, th~rmal weldi~g, or ~ther ~uit~le mea~ he impedance ma~shing circuits 50 and 70 ~an be ~abricated ~ circuit ~01~50 ~ S83P21 boards which can also be secured to, or housed in base men~b~r 100.
The base member 100 has secured to it a pair of hinge blocks lll and 112. The hinge blocks is lll and ll~
have ~ores through which legs 31 and 32 of loop 30 rotatably extend, The ends of the legs 31 and 32 ar~ held rotatably in a rearwardly extending tongue lOOa formed centrally on base ~ember 100. The hinge blocks 111 ~nd 112 and tongue lOOa support the loop 30 for rotation relative to the base me~ber lO0 to change the included angle ~ between the ~rltenr,a elements. The hinge blocks lll and 112 include ~roo~es 131 for a purpose described below. In the ront edge vf the base memher lOC, a notch 132 is provided. The offse~ portion 34 of the loop 30 is adapted to resiliently engage in the notch 13~ when the loop is folded (~ = 0) for stoxage or when the antenna apparatus is no~ being us~.
The base me~ber lO0 further has a downwardly ex~ending shaft 1410 A face gear 142 is mounted on a boss 143 molded integrally with the base me~mber 100~ The ~ha~t 141, which typically i~ made of metal (for m~ximum durability), i5 embedded in the bo~ 143 and is ~urrounded ~ the ~ace year 142. 'The shaft 141 provides a mounting means for the antenna apparatusO A moun~ 151y which csn be ~ecuxed tD the televison receiver, has a central hole 152 ~olded therein f~r r~tatably ~ccepting ~he ~haft 141~ ~he antenna apparatus can thu~ be rotated in ~he plane of base ~ember lO0 a~out the axis defined by shaft l~l~ The ~ount 151 also includes a ~aee ~ear 153 which confronts and ~cooper~tes with face ge~r 142 to prevent inadverta~t rotation vf the a~te~nh appar~tu~ . Thus I when he an enna 0~
S~1850 S~3P21 app~ratus has been directionally oriented, it is held in plac~ ~y ~ixing means, c~mprised of the faee gears 142 and 153~ again~t external r~tationa]. forces~ such as~ -that exexted by coaxial cable 51 when the antenna apparatus is ro~a~ed~
Referring n~w to FIG. 3, it will be seent ha~ an antenna apparatus in accordance with the present invention is very compact as compare~ ~ith the known one dimensional antenn~. ~lements commonly used in the prior art. Typic~lly, the total length ~1 of the operative antenna sho~n in FIG.
3 is sli~htly in excess of l meter~ which is about 0.3 to 0~35 ~imes the wavelenyth of signals in the ~HF low-band~
~ith such value of the lenyth 21o the antenna ~ecomes parallel-re~onall~ with signals having a ~requency of about 150 MHz, the wavelength ~f wh.ich is about 2 meters. It will ~urther be seen that the dimensions of the loop 30 and of ~he ~lates 10, 20, all of ~h~ch are shown in millimeters, ar~ such ~hat the L-shaped plates 10l 20 and the plates 61, ~2 therebe~ween can nest within loop .iO when the latter is foldedu E'IG. 4 graphically illust~ates the resi~tance R
~nd xeactance X in ohms (Q~ plotted again~t 21/~ , where 21 is the length of a loop, as ~hown in FIG. 3~ and ~
~epresent~ the wavelength 9f the ~ignal being received. As FIGo ~ illustrates5 with a ~iqnal o~ abou~ lOOMHz ~he wave:length of which is about 3 meters~ the r actance X is inductive, ~nd the reactanc~ becomes capac~tative with ~a ~ignal of ~bout 200~Hz J the wavelength of which i~ ~b~ut 1 D 5 m~ters. The ~esi~tance comp~nent i~ a~ut 10.~ a~ lOO~z and ~bout 100 Q ~t 200P~z. In ~he VHF high-band ~channels 4-12, S~185~
or freqllencies between about 170 MHz and 222 MHz) such a ~ntDJlna can be madP wide-band resonant by ~irtue of the ma~Ghing circuit 50 to provide coverage of the entire VHF
~igh~b~d. For the YHF low-band (frequencies of between 90 ~z and 108~.Hz), however, since the radiation resistance is sm~ the receiving bandwidth is decreased and neither the whole V~F low-band nor the requisite 6MHz bandwidth can be co~ered under ~hose conditions. Although for VSWR (Voltage ~Standlng Wave Ratio) values of about 2 to 3, the requisite ch2nnel bandwidth can be o~tained, it still is no~ possible ~o oover ~he entire VHF low-bandO However, in the antenna apparatus according to the presen~ invention, ~he adjustability of the angle ~ enables the coupling capclcitance to be changed so that the resonant frequency ~an be changed for each channel in the VH]? low band, and the entire low-band region of the VHF also can be covered by the antenna appaxa~us of the present invention.
FI~. S is a Smith chart which graphically illustxate6 the impedance characteristics of the antenna ~mboding the present i~vention for various values of the ~n~le (3 ~ The solid li~e in ~IG. 5 represents the impedance a~ ~- 180 and the do~ted line represen~s the impedance at ~- 0~O The impedance is ~hown for various frequencies ~90~z~ 93MHz, 105MHz and 220MHz~ Note tha~ the impedance characteristics of the antenna for ~ 0 and = lB0 are the ~ame ~bove a certain frequency~
FIG. 6 ~hows t~e gain characteristie~ of the an~enna ~pparatus of the presenk invention. In FI~ h2 ~oIid lines represent the antenna apparatus of the present invention and the dashed lines repre5ent the values fo~
;8 dlpole antenna, such ~s the rabbit ears used in the prior ar~ 6 illus~rates ~hat the small, compact antenna as ~hown .in FIG. 3 has impedance and gain characteristie~
~omparab`le to the characteristics of a dipole antenna having ~ntenn~ elements about 90 cm. long.
The antenna apparatus of the present invention is ~hus a wide-band resonan~ type in ~he high~band region of VHF ~ignals and is also resonant at Pach channel ~requency in ~he k~w-band xegior~ of the VHF signals, where radiation resistanee is small, by virtue of th~ ~apability of varying ~he ang~e ~.
It is, c course, known in the prior art that the resonant requency of an antenna can be changed with a ~a;racto~ diode. However, such ~evices are disadvantageous because ~hey require a control voltage, which increases the cost of ~he antenna~ and because non-linear distortion can be produced in the presence of the resulting electrical fieldO Eowever, with t.he present inY~ntion ~ ~uch increases in cost are prevented and non linear distortion is avoided becau~e it is the adjustment o the anyle ~ which varies ~he resonant: ~requency of the antennaO Furthermore, the grooves 131 in ~he blocks 111 and 112 enable the angle ~ to be set in sueh a way that it w.ill no~ be inadvertantly changed.
As th~se ~killed in ~e art will appreciate; the gain ~ the present antenna ~pparatus is increased because the legs 12 ~nd 22 of the plates 10 and 20~ respec~ively~
tap2r to ~he ~ontact point~ 13 and 23 ~o tha~ the voltage at .hose points i~ increased~ The leg p~rtion~ 1 and 3~ o~
the loop 30 al50 increase the gain of the antenn~ apparatus of ~he p~esent invention~
_.9 ~6~i S83P214 The pr~sent invention has been described in connec~ion with particular ~tructure. Those skilled in the art ~il1 cecognize var.iou~ modifications other than those ~pecifically pointed out which can be made to the embQdimen~s o he present invention described herein without departing from the spirit of the inventivn. For ex~mplel the two antenna elements can be made in more than ~wo dimensions. Th~refore t the ~cope of the present ;nvention is defin2d solely by the claims which follow.
~ 10-
Claims (16)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An antenna apparatus comprising:
a multi-dimensional first antenna element comprised of a wire formed into a loop in a first plane, said loop being generally in the form of a rectangle with the ends of said wire having a gap therebetween along one long side of said rectangle;
a multi-dimensional second antenna element comprised of a plurality of plate members disposed in a second plane and including at least two L-shaped plates with the ends of one legs of said plates in mutually facing relationship and the ends of the other legs of said plates facing said one long side of said rectangle of the loop;
means for mounting said first and second antenna elements rotatable with respect to each other for adjustment of an angle between said first and second antenna elements, the long side of said rectangle loop having said gap being rotatable mounted in respect to said second antenna element; and connecting means for electrically connecting said first and second antenna elements.
a multi-dimensional first antenna element comprised of a wire formed into a loop in a first plane, said loop being generally in the form of a rectangle with the ends of said wire having a gap therebetween along one long side of said rectangle;
a multi-dimensional second antenna element comprised of a plurality of plate members disposed in a second plane and including at least two L-shaped plates with the ends of one legs of said plates in mutually facing relationship and the ends of the other legs of said plates facing said one long side of said rectangle of the loop;
means for mounting said first and second antenna elements rotatable with respect to each other for adjustment of an angle between said first and second antenna elements, the long side of said rectangle loop having said gap being rotatable mounted in respect to said second antenna element; and connecting means for electrically connecting said first and second antenna elements.
2. The antenna apparatus as in claim 1; wherein said connecting means includes a pair of coiled spring elements each having a wound portion encircling said wire and ending in fingers extending therefrom and secured proximate to said end of said other leg of a respective one of said plates.
-
-
3. The antenna apparatus as in claim 1; further comprising a planar third antenna element disposed in the plane of said second antenna element between the legs of said L-shaped plates.
4. The antenna apparatus as in claim 3; wherein said third antenna element comprises a pair of plate elements.
5. The antenna apparatus as in claim 1; wherein said second antenna element includes a base member of a plastic material to which said L-shaped plates are attached.
6. The antenna apparatus as in claim 5; further comprising a matching circuit for matching the impedance of said antenna apparatus to the impedance of a lead for carrying a signal from the apparatus.
7. The antenna apparatus as in claim 6; wherein said matching circuit is attached to said base member.
8. The antenna apparatus as in claim 5; wherein said base member includes hinge blocks secured to said base member for pivotally mounting said loop thereon.
9. The antenna apparatus as in claim 8; wherein said base includes a tongue portion having the ends of said loop mounted therein.
10. The antenna apparatus as in claim 8; wherein said hinge blocks have grooves therein for holding said loop in a plurality of predetermined angles relative to said base member.
11. The antenna apparatus as in claim 5; further comprising a mounting member adapted to be secured on a receiver for accepting the signal received by the antenna apparatus, said base member having a shaft secured thereto for mounting said base member for rotation relative to said mounting member.
12. The antenna apparatus as in claim 11; wherein said mounting member and said base member include fixing means for releasably holding said base member in a plurality of predetermined angular positions relative to said mounting member.
13. The antenna apparatus us as in claim 12; wherein said fixing means comprises cooperating face gears on said movement and said base member.
14. The antenna apparatus as in claim 5; wherein said loop includes an of offset portion in the other long side of said rectangle and said base member has a notch in one edge thereof for accepting said offset portion to hold said loop in a closed position in which said included angle is zero.
15. A compact antenna apparatus for use as an indoor antenna for a television receiver, the antenna apparatus comprising:
a first planar antenna element comprising a conductive wire formed into a rectangular loop;
a planar rectangular plastic base member;
a second planar antenna element comprising a pair of plates secured to said base member in the plane thereof and electrically connected to said loop to form a VHF
antenna therewith;
a third planar antenna element comprising a pair of plates secured to said base member in the plane thereof to form a UHF antenna;
matching circuit means secured to said base members for matching the impedance of said VHF and UHF antennas to leads from the television receiver for the signals received thereby;
hinge means rotatably connecting a long side of said loop to a long side of said base member for adjustment of the included angle between the planes of said loop and base members and mounting means for rotatably mounting said base member to the television receiver.
a first planar antenna element comprising a conductive wire formed into a rectangular loop;
a planar rectangular plastic base member;
a second planar antenna element comprising a pair of plates secured to said base member in the plane thereof and electrically connected to said loop to form a VHF
antenna therewith;
a third planar antenna element comprising a pair of plates secured to said base member in the plane thereof to form a UHF antenna;
matching circuit means secured to said base members for matching the impedance of said VHF and UHF antennas to leads from the television receiver for the signals received thereby;
hinge means rotatably connecting a long side of said loop to a long side of said base member for adjustment of the included angle between the planes of said loop and base members and mounting means for rotatably mounting said base member to the television receiver.
16. The antenna apparatus as in claim 15; wherein said loop is about 40 cm by 8 cm and said base member is slightly smaller to permit nesting of said base member within said loop when the latter is folded flat into the plane of the base member.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP189861/82 | 1982-10-28 | ||
| JP57189861A JPS5979603A (en) | 1982-10-28 | 1982-10-28 | Antenna |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1206256A true CA1206256A (en) | 1986-06-17 |
Family
ID=16248406
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000439634A Expired CA1206256A (en) | 1982-10-28 | 1983-10-25 | Compact, adjustable antenna |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4570165A (en) |
| JP (1) | JPS5979603A (en) |
| KR (1) | KR920001063B1 (en) |
| CA (1) | CA1206256A (en) |
| DE (1) | DE3339278A1 (en) |
| FR (1) | FR2535532B1 (en) |
| GB (1) | GB2130802B (en) |
| NL (1) | NL189986C (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0758641B2 (en) * | 1986-10-31 | 1995-06-21 | ロ−ム株式会社 | Chip resistor |
| NL9100111A (en) * | 1991-01-23 | 1992-08-17 | Texas Instruments Holland | ANTENNA SYSTEM FOR AN INQUIRY STATION FOR IDENTIFYING OBJECTS. |
| US5923298A (en) * | 1997-04-30 | 1999-07-13 | Ford Motor Company | Multiband reception antenna for terrestrial digital audio broadcast bands |
| JP2002528984A (en) * | 1998-10-26 | 2002-09-03 | ティーディーケイ アールエフ ソリューションズ インコーポレイテッド | Broadband antennas including electrical and magnetic dipole radiators |
| US6448930B1 (en) | 1999-10-15 | 2002-09-10 | Andrew Corporation | Indoor antenna |
| US6160514A (en) * | 1999-10-15 | 2000-12-12 | Andrew Corporation | L-shaped indoor antenna |
| CA2397430A1 (en) * | 2000-01-14 | 2001-07-19 | Breck W. Lovinggood | Repeaters for wireless communication systems |
| US7623868B2 (en) * | 2002-09-16 | 2009-11-24 | Andrew Llc | Multi-band wireless access point comprising coextensive coverage regions |
| US20040203804A1 (en) * | 2003-01-03 | 2004-10-14 | Andrew Corporation | Reduction of intermodualtion product interference in a network having sectorized access points |
| US7091925B1 (en) * | 2005-01-28 | 2006-08-15 | Trans Electric Co., Ltd. | Flat indoor UHF antenna device for a digital television |
| KR100973489B1 (en) * | 2008-05-01 | 2010-08-03 | 주식회사 모비텍 | Intenna for adjusting beam directivity degree |
| US10195445B2 (en) * | 2015-06-11 | 2019-02-05 | Cardiac Pacemakers, Inc. | Bent loop antenna for implantable medical devices |
Family Cites Families (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE569256A (en) * | ||||
| US1386840A (en) * | 1919-11-29 | 1921-08-09 | Gen Electric | Radiosignaling system |
| GB315944A (en) * | 1928-05-14 | 1929-07-25 | Frederick Alexander | Improvements relating to paper carriages for typewriting-machines |
| GB581762A (en) * | 1940-07-10 | 1946-10-24 | Univ Leland Stanford Junior | Improvements relating to directional propagation and reception of electromagnetic waves |
| US2378663A (en) * | 1942-01-16 | 1945-06-19 | Zenith Radio Corp | Radio receiver |
| US2388567A (en) * | 1943-01-28 | 1945-11-06 | Philco Radio & Television Corp | Portable radio receiver |
| GB589136A (en) * | 1943-06-05 | 1947-06-12 | Western Electric Co | Improvements in or relating to directive radio systems |
| US2545959A (en) * | 1947-09-03 | 1951-03-20 | Illinois Watch Case Co | Radio apparatus construction |
| US2632849A (en) * | 1949-10-11 | 1953-03-24 | Motorola Inc | Television antenna |
| DE957855C (en) * | 1954-06-18 | 1957-01-17 | Electric &. Musical Industries Ltd Hayes, Middlesex (Großbritannien) | Antenna arrangement for at least two preferably non-adjacent frequency bands |
| FR1117068A (en) * | 1955-01-07 | 1956-05-16 | Indoor TV antenna | |
| DE1036941B (en) * | 1957-06-15 | 1958-08-21 | Telefunken Gmbh | Directional antenna arrangement |
| US3290689A (en) * | 1964-05-11 | 1966-12-06 | Packard Bell Electronics Corp | Angularly adjustable folded dipole |
| US3478361A (en) * | 1968-10-09 | 1969-11-11 | Marvin P Middlemark | Indoor television antenna with rotatable rings |
| US3522608A (en) * | 1969-02-19 | 1970-08-04 | Gen Electric | Telescoping vhf-uhf antenna for a television receiver |
| DE1916062A1 (en) * | 1969-03-28 | 1970-10-08 | Mitsubishi Export & Imp Gmbh D | Antenna arrangement, in particular television antenna |
| US3587101A (en) * | 1969-11-13 | 1971-06-22 | Television Laboratoriese Inc | Pivotable antenna |
| JPS558967Y2 (en) * | 1974-08-20 | 1980-02-27 | ||
| DE2745659A1 (en) * | 1976-10-14 | 1978-04-20 | Mecaniplast S A | RECEIVER ANTENNA |
-
1982
- 1982-10-28 JP JP57189861A patent/JPS5979603A/en active Granted
-
1983
- 1983-10-25 CA CA000439634A patent/CA1206256A/en not_active Expired
- 1983-10-26 NL NLAANVRAGE8303693,A patent/NL189986C/en not_active IP Right Cessation
- 1983-10-27 FR FR8317200A patent/FR2535532B1/en not_active Expired
- 1983-10-27 US US06/545,932 patent/US4570165A/en not_active Expired - Fee Related
- 1983-10-27 KR KR1019830005083A patent/KR920001063B1/en not_active IP Right Cessation
- 1983-10-28 DE DE19833339278 patent/DE3339278A1/en active Granted
- 1983-10-28 GB GB08328849A patent/GB2130802B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2130802A (en) | 1984-06-06 |
| NL8303693A (en) | 1984-05-16 |
| US4570165A (en) | 1986-02-11 |
| KR920001063B1 (en) | 1992-02-01 |
| JPH0340963B2 (en) | 1991-06-20 |
| KR840006574A (en) | 1984-11-30 |
| FR2535532B1 (en) | 1987-01-16 |
| FR2535532A1 (en) | 1984-05-04 |
| GB8328849D0 (en) | 1983-11-30 |
| DE3339278C2 (en) | 1993-05-27 |
| DE3339278A1 (en) | 1984-05-10 |
| GB2130802B (en) | 1986-02-05 |
| NL189986C (en) | 1993-09-16 |
| NL189986B (en) | 1993-04-16 |
| JPS5979603A (en) | 1984-05-08 |
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